Premium
The polymorphism of some liquid crystalline 4′‐n‐alkyloxy‐3′‐nitro‐biphenylcarboxylic acids
Author(s) -
Demus D.,
Marzotko D.,
Sharma N. K.,
Wiegeleben A.
Publication year - 1980
Publication title -
kristall und technik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0023-4753
DOI - 10.1002/crat.19800150315
Subject(s) - supercooling , homologous series , metastability , liquid crystal , polymorphism (computer science) , crystallography , phase transition , calorimetry , optical microscope , nitro , phase (matter) , chemistry , materials science , thermodynamics , organic chemistry , physics , alkyl , biochemistry , optoelectronics , gene , scanning electron microscope , genotype , composite material
The substances of the homologous serieswith n = 6, 12, 14, 15, 16, 18 were investigated by calorimetry and microscopy. In the lower members exist nematic, smectic A and smectic C phases, in the homologs with n = 16 and 18 appear phases of the type smectic D with cubic structure. The kinetics of these phase transitions, in which smectic D is participating shows a strong dependence upon the experimental conditions. Supercooling, as well as, overheating effects were found. In the supercooled state we could detect for the first time smectic phases, which are metastable with respect to another liquid crystalline phase (S D ).